/* Lifeline — hyper-minimal, Linear-grade dark theme.
   The "lifeline" is a single luminous thread running horizontally across the whole site;
   the vertical wheel traverses it. Content is real semantic HTML (GEO-first); the horizontal
   layout + wheel→scroll is progressive enhancement. On small screens it stacks vertically. */

:root {
  --bg: #08090a;
  --bg-elev: #0d0e10;
  --bg-elev-2: #131417;
  --ink: #f7f8f8;
  --ink-dim: #b7bdc6;
  --ink-mute: #8a8f98;
  --ink-faint: #5b606b;
  --line: rgba(255, 255, 255, 0.08);
  --line-strong: rgba(255, 255, 255, 0.14);
  --accent: #7c89ff;       /* indigo thread */
  --accent-2: #41d6c3;     /* cyan tail */
  --accent-glow: rgba(124, 137, 255, 0.45);
  --radius: 10px;
  --maxw: 1180px;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);

  --font: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --mono: "JetBrains Mono", ui-monospace, "SF Mono", "Menlo", "Consolas", monospace;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }

body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--ink);
  font-size: 17px;
  line-height: 1.6;
  letter-spacing: -0.011em;
  font-feature-settings: "ss01", "cv11";
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow: hidden;            /* landing controls its own scroll; docs override below */
}

::selection { background: var(--accent-glow); color: #fff; }

a { color: inherit; text-decoration: none; transition: color 0.18s var(--ease); }
a:hover { color: #fff; }

code, pre, .mono { font-family: var(--mono); font-feature-settings: normal; }

h1, h2, h3 { font-weight: 560; letter-spacing: -0.025em; line-height: 1.08; }

/* ---------- ambient background: faint grid + radial wash ---------- */
.bg-fx {
  position: fixed; inset: 0; z-index: 0; pointer-events: none;
  background:
    radial-gradient(1200px 600px at 18% 30%, rgba(124, 137, 255, 0.10), transparent 60%),
    radial-gradient(900px 500px at 85% 75%, rgba(65, 214, 195, 0.06), transparent 60%);
}
.bg-grid {
  position: fixed; inset: 0; z-index: 0; pointer-events: none; opacity: 0.5;
  background-image:
    linear-gradient(var(--line) 1px, transparent 1px),
    linear-gradient(90deg, var(--line) 1px, transparent 1px);
  background-size: 64px 64px;
  -webkit-mask-image: radial-gradient(circle at 50% 50%, #000 0%, transparent 78%);
          mask-image: radial-gradient(circle at 50% 50%, #000 0%, transparent 78%);
}

/* ================= TOP BAR ================= */
.topbar {
  position: fixed; top: 0; left: 0; right: 0; z-index: 50;
  display: flex; align-items: center; justify-content: space-between;
  padding: 18px 28px;
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
}
.brand { display: flex; align-items: center; gap: 10px; font-weight: 560; letter-spacing: -0.02em; }
.brand .dot {
  width: 9px; height: 9px; border-radius: 50%;
  background: var(--accent); box-shadow: 0 0 14px 1px var(--accent-glow);
}
.brand .brandmark { width: 22px; height: 22px; color: var(--accent); filter: drop-shadow(0 0 7px var(--accent-glow)); flex: none; }
.brand .ver { color: var(--ink-faint); font: 500 12px/1 var(--mono); margin-left: 2px; }
.topnav { display: flex; align-items: center; gap: 26px; font-size: 14.5px; color: var(--ink-mute); }
.topnav a:hover { color: var(--ink); }
.topnav .pill {
  border: 1px solid var(--line-strong); border-radius: 999px; padding: 7px 15px; color: var(--ink-dim);
  transition: border-color 0.18s var(--ease), color 0.18s var(--ease);
}
.topnav .pill:hover { border-color: var(--accent); color: #fff; }

/* ================= HORIZONTAL TRACK ================= */
.track {
  position: relative; z-index: 1;
  display: flex; flex-flow: row nowrap;
  height: 100vh; height: 100dvh;
  overflow-x: auto; overflow-y: hidden;
  scroll-snap-type: none;   /* native snap (mandatory OR proximity) reverts wheel increments near a panel → freeze. JS snaps on idle instead. */
  scrollbar-width: none;
}
.track::-webkit-scrollbar { display: none; }

.panel {
  position: relative;
  flex: 0 0 100vw; width: 100vw;
  height: 100vh; height: 100dvh;
  scroll-snap-align: center;
  display: flex; align-items: center;
  padding: 0 max(28px, 7vw);
}
.panel-inner { width: 100%; max-width: var(--maxw); margin: 0 auto; }

/* the persistent lifeline thread (drawn behind panels, fixed vertically) */
.thread {
  position: fixed; left: 0; right: 0; top: 50%; z-index: 0; height: 2px; pointer-events: none;
  background: linear-gradient(90deg, transparent, var(--line-strong) 6%, var(--line-strong) 94%, transparent);
}
.thread .fill {
  position: absolute; left: 0; top: 0; height: 100%; width: 0;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  box-shadow: 0 0 16px 1px var(--accent-glow);
  transition: width 0.12s linear;
}

/* node marker per panel, sitting on the thread */
.node {
  position: absolute; top: calc(50% - 5px); left: max(28px, 7vw);
  width: 10px; height: 10px; border-radius: 50%;
  background: var(--bg); border: 1.5px solid var(--ink-faint);
}
.panel.seen .node { border-color: var(--accent); box-shadow: 0 0 12px 1px var(--accent-glow); }

/* ================= TYPE / CONTENT ================= */
.eyebrow {
  display: inline-flex; align-items: center; gap: 9px;
  font: 500 12.5px/1 var(--mono); letter-spacing: 0.02em;
  color: var(--ink-mute); text-transform: none; margin-bottom: 22px;
}
.hash { color: var(--accent); }
.eyebrow .bar { width: 22px; height: 1px; background: var(--line-strong); }

.display {
  font-size: clamp(40px, 6.4vw, 86px); font-weight: 580; letter-spacing: -0.035em; line-height: 0.98;
}
.display .grad {
  background: linear-gradient(96deg, var(--ink) 30%, var(--accent) 70%, var(--accent-2));
  -webkit-background-clip: text; background-clip: text; -webkit-text-fill-color: transparent;
}
h2.title { font-size: clamp(30px, 4vw, 52px); letter-spacing: -0.03em; }

.lead { color: var(--ink-dim); font-size: clamp(17px, 1.5vw, 21px); line-height: 1.5; max-width: 60ch; margin-top: 22px; }
.muted { color: var(--ink-mute); }
.body { color: var(--ink-dim); max-width: 62ch; margin-top: 16px; }
.body strong { color: var(--ink); font-weight: 560; }

/* CTA row */
.cta { display: flex; flex-wrap: wrap; gap: 14px; margin-top: 38px; align-items: center; }
.btn {
  display: inline-flex; align-items: center; gap: 9px;
  padding: 12px 20px; border-radius: var(--radius); font-size: 15px; font-weight: 540;
  border: 1px solid transparent; transition: all 0.18s var(--ease); white-space: nowrap;
}
.btn-primary { background: var(--ink); color: #0a0b0c; }
.btn-primary:hover { color: #0a0b0c; transform: translateY(-1px); box-shadow: 0 8px 30px rgba(255,255,255,0.12); }
.btn-ghost { border-color: var(--line-strong); color: var(--ink-dim); }
.btn-ghost:hover { border-color: var(--accent); color: #fff; }

.copy {
  display: inline-flex; align-items: center; gap: 12px;
  background: var(--bg-elev); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 12px 16px; font: 500 14.5px/1 var(--mono); color: var(--ink-dim); cursor: pointer;
  transition: border-color 0.18s var(--ease);
}
.copy:hover { border-color: var(--line-strong); }
.copy .prompt { color: var(--accent); }
.copy .ic { color: var(--ink-faint); font-size: 12px; }

/* feature grids / cards */
.grid { display: grid; gap: 18px; margin-top: 40px; }
.grid.cols-3 { grid-template-columns: repeat(3, 1fr); }
.grid.cols-2 { grid-template-columns: repeat(2, 1fr); }
.card {
  border: 1px solid var(--line); border-radius: var(--radius); padding: 24px 22px;
  background: linear-gradient(180deg, var(--bg-elev), rgba(13,14,16,0.4));
  transition: border-color 0.2s var(--ease), transform 0.2s var(--ease);
}
.card:hover { border-color: var(--line-strong); transform: translateY(-2px); }
.card .k { font: 600 12px/1 var(--mono); color: var(--accent); letter-spacing: 0.04em; }
.card h3 { font-size: 18px; margin: 14px 0 8px; font-weight: 560; letter-spacing: -0.02em; }
.card p { color: var(--ink-mute); font-size: 14.5px; line-height: 1.5; }

/* law list */
.laws { display: grid; grid-template-columns: repeat(2, 1fr); gap: 2px 38px; margin-top: 36px; }
.law { display: flex; gap: 16px; padding: 15px 0; border-bottom: 1px solid var(--line); }
.law .n { font: 600 13px/1.4 var(--mono); color: var(--accent); min-width: 22px; }
.law .t { color: var(--ink-dim); font-size: 15px; }
.law .t b { color: var(--ink); font-weight: 560; }

/* steps / loop */
.steps { display: grid; grid-template-columns: repeat(2, 1fr); gap: 18px; margin-top: 36px; }
.step { border: 1px solid var(--line); border-radius: var(--radius); padding: 22px; background: var(--bg-elev); }
.step .badge { font: 600 11px/1 var(--mono); color: var(--bg); background: var(--accent); padding: 5px 9px; border-radius: 5px; }
.step h3 { font-size: 16.5px; margin: 16px 0 8px; }
.step p { color: var(--ink-mute); font-size: 14px; }
.step code { color: var(--ink-dim); background: var(--bg-elev-2); padding: 2px 7px; border-radius: 5px; font-size: 13px; }

/* code block */
pre.code {
  margin-top: 24px; background: var(--bg-elev); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 20px 22px; overflow-x: auto; font: 500 13.5px/1.7 var(--mono); color: var(--ink-dim);
}
pre.code .c { color: var(--ink-faint); }     /* comment */
pre.code .a { color: var(--accent); }          /* command */
pre.code .s { color: var(--accent-2); }        /* string */

/* docs hub list (last panel) */
.doclist { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; margin-top: 34px; }
.doclink {
  border: 1px solid var(--line); border-radius: var(--radius); padding: 18px;
  display: flex; flex-direction: column; gap: 6px; background: var(--bg-elev);
  transition: border-color 0.18s var(--ease), transform 0.18s var(--ease);
}
.doclink:hover { border-color: var(--accent); transform: translateY(-2px); }
.doclink .t { font-weight: 560; font-size: 15.5px; }
.doclink .d { color: var(--ink-mute); font-size: 13px; }
.doclink .arrow { color: var(--accent); }

/* ================= SIDE NAV (dots) ================= */
.dots { position: fixed; right: 26px; top: 50%; transform: translateY(-50%); z-index: 40; display: flex; flex-direction: column; gap: 13px; }
.dots button {
  width: 9px; height: 9px; border-radius: 50%; border: 0; padding: 0; cursor: pointer;
  background: var(--ink-faint); opacity: 0.55; transition: all 0.2s var(--ease); position: relative;
}
.dots button:hover { opacity: 1; transform: scale(1.25); }
.dots button.active { background: var(--accent); opacity: 1; box-shadow: 0 0 12px 1px var(--accent-glow); }
.dots button::after {
  content: attr(data-label); position: absolute; right: 20px; top: 50%; transform: translateY(-50%);
  font: 500 11px/1 var(--mono); color: var(--ink-mute); white-space: nowrap; opacity: 0;
  transition: opacity 0.18s var(--ease); pointer-events: none;
}
.dots button:hover::after { opacity: 1; }

/* progress hint (vertical wheel → horizontal) */
.scroll-hint {
  position: fixed; bottom: 26px; left: 50%; transform: translateX(-50%); z-index: 40;
  font: 500 12px/1 var(--mono); color: var(--ink-faint); display: flex; align-items: center; gap: 10px;
  transition: opacity 0.4s var(--ease);
}
.scroll-hint .key { border: 1px solid var(--line-strong); border-radius: 5px; padding: 3px 7px; color: var(--ink-mute); }

/* keyframe reveal */
.reveal { opacity: 0; transform: translateY(14px); transition: opacity 0.7s var(--ease), transform 0.7s var(--ease); }
.panel.seen .reveal { opacity: 1; transform: none; }
.panel.seen .reveal.d1 { transition-delay: 0.06s; }
.panel.seen .reveal.d2 { transition-delay: 0.12s; }
.panel.seen .reveal.d3 { transition-delay: 0.18s; }

/* ================= RESPONSIVE: stack vertically on touch/small ================= */
@media (max-width: 860px) {
  body { overflow-y: auto; overflow-x: hidden; }
  .track { display: block; height: auto; overflow: visible; scroll-snap-type: none; }
  .panel { width: 100%; min-height: auto; height: auto; padding: 96px max(22px, 6vw) 64px; scroll-snap-align: none; }
  .thread, .node, .dots, .scroll-hint, .bg-grid { display: none; }
  .grid.cols-3, .grid.cols-2, .laws, .steps, .doclist { grid-template-columns: 1fr; }
  .reveal { opacity: 1; transform: none; }
  .display { font-size: clamp(36px, 12vw, 56px); }
}

/* ================= REDUCED MOTION ================= */
@media (prefers-reduced-motion: reduce) {
  * { scroll-behavior: auto !important; }
  .reveal { opacity: 1 !important; transform: none !important; transition: none; }
  .thread .fill { transition: none; }
}

/* ================= DOCS PAGES (vertical, readable) ================= */
body.docs { overflow: auto; }
.docs-shell { position: relative; z-index: 1; max-width: 1080px; margin: 0 auto; padding: 96px 28px 120px; display: grid; grid-template-columns: 230px 1fr; gap: 56px; }
.docs-side { position: sticky; top: 96px; align-self: start; height: max-content; }
.docs-side .group { font: 600 11px/1 var(--mono); color: var(--ink-faint); letter-spacing: 0.08em; text-transform: uppercase; margin: 22px 0 10px; }
.docs-side a { display: block; color: var(--ink-mute); font-size: 14.5px; padding: 7px 12px; border-radius: 7px; transition: all 0.15s var(--ease); border-left: 2px solid transparent; }
.docs-side a:hover { color: var(--ink); background: var(--bg-elev); }
.docs-side a.current { color: #fff; border-left-color: var(--accent); background: var(--bg-elev); }
.docs-main { min-width: 0; }
.docs-main h1 { font-size: clamp(32px, 4vw, 46px); letter-spacing: -0.03em; margin-bottom: 8px; }
.docs-main h2 { font-size: 26px; margin: 48px 0 14px; padding-top: 14px; border-top: 1px solid var(--line); letter-spacing: -0.02em; }
.docs-main h3 { font-size: 19px; margin: 30px 0 10px; }
.docs-main p { color: var(--ink-dim); margin: 14px 0; }
.docs-main ul, .docs-main ol { color: var(--ink-dim); margin: 14px 0 14px 22px; }
.docs-main li { margin: 7px 0; }
.docs-main a { color: var(--accent); }
.docs-main a:hover { color: var(--accent-2); }
.docs-main strong { color: var(--ink); font-weight: 560; }
.docs-main code { font-family: var(--mono); font-size: 0.88em; background: var(--bg-elev-2); border: 1px solid var(--line); padding: 1px 6px; border-radius: 5px; color: var(--ink); }
.docs-main pre { background: var(--bg-elev); border: 1px solid var(--line); border-radius: var(--radius); padding: 18px 20px; overflow-x: auto; margin: 18px 0; }
.docs-main pre code { background: none; border: 0; padding: 0; font-size: 13.5px; line-height: 1.7; color: var(--ink-dim); }
.docs-main blockquote { border-left: 2px solid var(--accent); padding: 4px 0 4px 18px; margin: 18px 0; color: var(--ink-mute); }
.docs-main table { width: 100%; border-collapse: collapse; margin: 20px 0; font-size: 14.5px; }
.docs-main th, .docs-main td { text-align: left; padding: 10px 14px; border-bottom: 1px solid var(--line); }
.docs-main th { color: var(--ink); font-weight: 560; }
.docs-main td { color: var(--ink-mute); }
.docs-main hr { border: 0; border-top: 1px solid var(--line); margin: 40px 0; }
.docs-lead { color: var(--ink-mute); font-size: 18px; margin: 10px 0 30px; }
.docs-foot { border-top: 1px solid var(--line); margin-top: 64px; padding-top: 24px; color: var(--ink-faint); font-size: 13.5px; display: flex; justify-content: space-between; flex-wrap: wrap; gap: 12px; }
@media (max-width: 860px) { .docs-shell { grid-template-columns: 1fr; gap: 0; padding-top: 88px; } .docs-side { position: static; margin-bottom: 30px; } }

/* footer (landing last panel) */
.foot { display: flex; justify-content: space-between; align-items: flex-end; gap: 20px; margin-top: 52px; padding-top: 24px; border-top: 1px solid var(--line); color: var(--ink-faint); font-size: 13.5px; flex-wrap: wrap; }
.foot a { color: var(--ink-mute); }
.foot a:hover { color: var(--ink); }

/* diagrams (inline SVG: the loop, the reasoning DAG) */
.diagram { display: block; width: 100%; max-width: 720px; height: auto; }
.panel .diagram { margin: 14px auto 2px; max-width: 660px; }
.diagram-fig { margin: 28px 0; }
.diagram-fig .diagram { margin: 0 auto; }
.diagram-fig figcaption { color: var(--ink-faint); font: 500 12.5px/1.55 var(--mono); text-align: center; margin-top: 10px; }